The present invention relates to data transmitting techniques which provide image data to thermal print head (TPH) in a facsimile system or the like and, more particularly, to a data transmitting apparatus for the thermal print head (TPH) of high density with a plurality of data input lines adopted to increase thermal printing speed.
A conventional facsimile system has utilized the thermal print head (TPH) with only one data input line. Therefore, it took a long time to print the image data by the TPH because the data was, in regular sequence, transmitted to the TPH by the data transmitting apparatus having only one image data memory.
By the way, in the conventional system, since the TPH had a low resolution and data transmission rate between Group III facsimile systems was slow, the data transmitting apparatus had no serious problem.
But, in a Group IV facsimile system connected to digital network a TPH has a high resolution, and data transmission rate between Group IV facsimile systems is very fast. Accordingly, a system for embodying the above conditions is required, and recently a data transmitting apparatus was suggested in order to increase thermal printing speed. The recent apparatus adopted a TPH of high density with a plurality of data input lines.
However, because the recent apparatus had only one image memory, several problems were caused. That is to say, in the case that the apparatus overall depends upon the only one image memory, although to print a high density image could be realized, but the above recent apparatus had difficulty in real time data processing, because it still took a long time to output the image data from the memory to the TPH through the data input lines, in sequence.